Current industry practice with various brass articles such as faucets, faucet escutcheons, door knobs, door handles, door escutcheons and the like, is to first buff and polish the surface of the article to a high gloss and to then apply a protective organic coating, such as one comprised of acrylics, urethanes, epoxies and the like, onto this polished surface. This system has the drawback that the buffing and polishing operation, particularly if the article is of a complex shape, is labor intensive. Also, the known organic coatings are not always as durable as desired, and are susceptible to attack by acids. It would, therefore, be quite advantageous if brass articles, or indeed other articles, either plastic, ceramic, or metallic, could be provided with coating which provided the article with a decorative appearance as well as providing wear resistance, abrasion resistance and corrosion resistance.
U.S. Pat. No. 7,270,895 represents a recent development in this technology. The patent discloses an article coated with a layer coating having a dark color. Preferably, the color is dark gray or a dark bronze color. The coating comprises a color and protective layer comprised of a refractory metal oxycarbide wherein the oxygen content is greater than the carbon content. The refractory metal typically is zirconium.
U.S. Pat. No. 8,007,928 represents another recent development in this technology. The patent discloses an article coated with a layer coating having a black color. The coating comprises a second color layer comprised of a refractory metal oxycarbide wherein the oxygen content is greater than the carbon content and a third layer comprised of a refractory metal oxide. The search for novel appearances not previously achievable continues.